This invention relates to a bending machine for the bending of tube, rod- or bar-shaped workpieces and especially of pipes and tubes. Such a bending machine has a base unit equipped with a collet as well as a tool assembly provided with at least one bending tool. The bending tool can be opened and closed in the transverse direction of the workpiece by the relative movement of tool components and forms at least one workpiece holder, and the tool assembly is mounted on and movable relative to a swivel support which is mounted on the machine base unit in such a fashion that it can be rotated around a swivel support axis of rotation extending in the longitudinal direction of the workpiece.
In bending machines of this type, it is necessary for various reasons to move the tool assembly relative to the machine base unit and/or relative to the workpiece held on it. For example, tool assemblies which for multi-level bending applications are equipped with several bending tools mounted one above the other, and they are moved relative to the machine base unit in a fashion so that each tool, as it is to be applied, can individually address the workpiece to be bent. Two-directional bending tool assemblies equipped with at least one bending tool for each bending direction are positioned relative to the machine base unit and to the workpiece held on it in a fashion so that, for each bending direction, the appropriate bending tool can be engaged. Finally, tool assemblies are also used for workpiece handling for which purpose they can be moved relative to the machine base unit.
A bending machine of the general type last mentioned is described in U.S. Pat. No. 5,927,126 granted Jul. 27, 1999. In that prior art design, the swivel support for the tool assembly is constituted of a platen that is mounted on a basic machine frame in a way to permit rotation around an axis that extends in the longitudinal direction of the workpiece. A slide on that platen guides the tool assembly in a linear direction perpendicular to the axis of rotation of the platen. Rotating the platen and linearly moving the slide allows the tool assembly of that earlier design, prior to or following the processing of the workpiece, to be moved into positions in which it can receive from a loading magazine workpieces to be processed using the components of a bending tool or in which these bending tool components can transfer processed workpieces to an unloading station.
The various positions of the tool assembly or of the work holder constituted by its bending tool can in each case be obtained by one single rotary position of the platen that linearly guides the slide of the tool assembly relative to the basic machine frame. For the linear movement of the slide on the platen, a powerful drive unit must be provided. The size of the linear drive system for the slide is a function of the length of travel of the slide and can be relatively bulky.
It is the objective of this invention to provide a novel bending machine which remedies the drawbacks of the prior art design.
It is also an object to provide such a bending machine which enables the forming of consecutive bends in an elongated workpiece without interference from the machine base as the workpiece is manipulated between positions and formed.